“If you are creating these works specifically for use with a software project, we generally recommend that you release your work under the same license as the software. There is no problem in doing so with the licenses we have recommended: GPLv3, LGPLv3, AGPLv3, and GPLv2 can all be applied to any kind of work—not just software—that is copyrightable and has a clear preferred form for modification. Using the same license as the software will help make compliance easier for distributors, and avoids any doubt about potential compatibility issues. Using a different free license may be appropriate if it provides some specific practical benefit, like better cooperation with other free projects. ” 里 “…… preferred form ……” 中的 “preferred” 是什么意思？